In many racing sports an athlete will compete (take part) in a time trial. This is when the athlete races over a course as fast as they can. In cross country skiing and biathlon competitions, a skier will start every 30 to 60 seconds. These are called interval starts. In cycling a time trial (TT) can be a single track race, or an individual time trial on the road. Time trials are often a part of a stage race, for example the Tour de France.
In a team time trial in cycling, a team of riders will race together. A group can ride faster than just one rider because riders following the leader are sheltered from the wind.
In rowing, time trial races, where the boats start every 10 to 20 seconds, are usually called "head races."